JPH06180298A - Water content measuring apparatus - Google Patents

Abstract

PURPOSE:To automate management of concrete by instantaneously obtaining water content of the concrete without requiring hands. CONSTITUTION:A resistance value and an electrostatic capacity of a ceramic element 5 for constituting a ceramic humidity sensor 1 are detected by fetching a detection signal to be output from the sensor 1 buried in concrete 4, and a temperature of the sensor 1 is detected by a temperature sensor 2 buried in the vicinity of the sensor 1. Constants Ar, Er, Ac, Ec of water contents stored in a memory 12 are read based on the temperature obtained by the detecting operation, and then water content W of the concrete 4 is calculated from the resistance value and the capacity of the element 5 by using an Arrhenius equation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water content measuring device for measuring the water content of concrete by means of a ceramic element embedded in the concrete.

[0002]

2. Description of the Related Art In concrete used in a nuclear power plant or the like, it is necessary to measure the water content in the concrete for the following reasons from the viewpoint of concrete management.

The first reason is that when moisture in concrete that constantly receives heat or radiation, for example, concrete that constitutes a shield wall of a nuclear power plant, evaporates and decreases, the strength of the concrete increases accordingly. Is reduced,
The shielding wall may collapse.

The second reason is that there is a close relationship between the rate of progress of the alkaline-aggregate reaction in concrete and the water content,
By controlling the water content, rust occurs in the reinforcing bars in the concrete,
When the covered portion of concrete collapses due to this rust and the reinforcing bar is exposed, it is necessary to repair and cover this portion.

The third reason is that the progress of drying shrinkage and neutralization of concrete and the development of strength depend on the water content. For these first to third reasons, when it is necessary to measure the water content of concrete, the water content measuring device is used to measure the water content of concrete.

This water content measuring device is a sensor embedded in concrete whose water content is to be measured, for example, a ceramic humidity sensor that changes its resistance value or electrostatic capacity by taking in ambient moisture, and this ceramic humidity sensor. And a measuring device main body that calculates the water content of the concrete based on the humidity of the concrete detected by the concrete, and the concrete detected by a ceramic humidity sensor embedded in the concrete whose water content is to be measured. The moisture content of the concrete is obtained by causing the measuring device main body to perform calculation based on the humidity of the above, and this is displayed on the CRT device or output from the printer device.

[0007]

However, the above-mentioned conventional water content measuring device has the following problems. That is, in such a water content measuring device, the water content of the concrete in which this ceramic humidity sensor is embedded is utilized by utilizing the fact that the resistance value and electrostatic capacity of the ceramic humidity sensor change in accordance with the amount of surrounding water. Although the measurement is performed, the ceramic element used in the ceramic humidity sensor changes its resistance value and electrostatic capacitance depending on the temperature. There was a problem that the water content of the concrete obtained in step 1 had to be corrected, and this correction work took time and effort.

In view of the above-mentioned circumstances, the present invention can instantly determine the water content of concrete without the need for manpower when determining the water content of concrete, which saves labor and time for measuring the water content of concrete. It is an object of the present invention to provide a water content measuring device which can be controlled to almost zero and which can automate the management of concrete.

[0009]

In order to achieve the above object, a water content measuring device according to the present invention comprises a ceramic humidity sensor embedded in concrete whose water content is to be measured, and Among them, a temperature sensor embedded in a portion corresponding to the ceramic humidity sensor, a humidity detecting unit that calculates the humidity of the concrete based on a detection signal output from the ceramic humidity sensor, and an output from the temperature sensor. A temperature detection unit that calculates the temperature of the ceramic humidity sensor portion based on a detection signal, a temperature characteristic data storage unit that stores temperature characteristic data of the ceramic humidity sensor, and the concrete obtained by the humidity detection unit. Humidity, the temperature of the ceramic humidity sensor obtained by the temperature detector, and the temperature characteristic data record. Based on the temperature characteristics data stored in the part being characterized in that a moisture content calculator for calculating the moisture content of the concrete.

[0010]

In the above structure, the humidity of the concrete is calculated based on the detection signal output from the ceramic humidity sensor embedded in the concrete by the humidity detecting section, and the humidity is embedded in the vicinity of the ceramic humidity sensor by the temperature detecting section. After the temperature of the ceramic humidity sensor portion is calculated based on the detection signal output from the temperature sensor, the humidity of the concrete obtained in the humidity detecting portion by the water content calculating portion and the temperature in the temperature detecting portion are obtained. The water content of the concrete is calculated based on the temperature of the ceramic humidity sensor and the temperature characteristic data of the ceramic humidity sensor stored in the temperature characteristic data storage unit.

[0011]

FIG. 1 is a block diagram showing an embodiment of a water content measuring device according to the present invention. The water content measuring device shown in this figure includes a ceramic humidity sensor 1, a temperature sensor 2, and a measuring device body 3.
Concrete whose water content is measured by 4
The humidity W (see FIG. 2) is measured to calculate the water content W, and the water content W is corrected based on the temperature of the ceramic humidity sensor 1 obtained by the temperature sensor 2 and output.

As shown in FIG. 2, the ceramic humidity sensor 1 includes a ceramic element 5 formed by adding potassium carbonate to ferric oxide or a zinc oxide and vanadium oxide as a main component, and each surface of the ceramic element 5. Each of them has two electrodes 6 attached thereto, is embedded in concrete 4 whose moisture content is to be measured, and when an excitation signal is output from the measuring device body 3, the humidity of the concrete 4 or A detection signal corresponding to the temperature is generated and supplied to the measuring device body 3.

In this case, since the ceramic element 5 is porous, when it is buried in the concrete 4, the water content in the concrete 4 enters the ceramic element 5 and the higher the water content, the more As shown in FIG. 6, the electric resistance value R decreases, and as shown in FIG. 6, the value of the electrostatic capacitance C increases.

The temperature sensor 2 is composed of a thermocouple 7, is embedded in the concrete 4 in the vicinity of the ceramic humidity sensor 1, and generates a thermoelectromotive voltage signal according to the temperature of the ceramic humidity sensor 1. Then, this is supplied to the measuring device body 3.

As shown in FIG. 1, the measuring apparatus body 3 includes a humidity detecting section 10, a temperature detecting section 11, a storage section 12, and a calibrating section 1.
3, the excitation signal is generated to drive the ceramic humidity sensor 1, while the detection signal output from the ceramic humidity sensor 1 is taken in to calculate the water content W of the concrete 4, The water content W is calibrated by referring to the temperature characteristic data of the ceramic humidity sensor 1 which is preset based on the thermoelectromotive force signal obtained by the sensor 2, and this is output.

As shown in FIG. 2, the humidity detecting section 10 includes an exciting circuit 14, a differential amplifier circuit 15, and a synchronizing signal generating circuit 16.
And a resistance value detection circuit 17 and a capacitance detection circuit 18. The ceramic humidity sensor 1 generates an excitation signal and supplies it to the ceramic humidity sensor 1 to drive it. The output detection signal is fetched and synchronously detected to obtain the resistance value and the electrostatic capacitance of the ceramic element 5, and the resistance value and the electrostatic capacitance are digitized to obtain resistance value data. , Capacitance data is generated and supplied to the calibration unit 13.

The excitation circuit 14 includes an AC constant voltage power supply 19 for generating an excitation signal (AC signal) having a preset frequency (for example, 1 Hz to 10 Hz) and a preset crest value, and this AC constant voltage power supply. And a reference resistor 20 that generates a reference signal based on the excitation signal output from 19. The AC constant voltage power supply 19 generates an excitation signal to drive the ceramic humidity sensor 1 and Generates a reference signal synchronized with the phase,
This is supplied to the synchronization signal generation circuit 16.

The synchronization signal generation circuit 16 is the excitation circuit 14 described above.
A differential amplifier circuit 21 for taking in and amplifying a reference signal output from the differential amplifier circuit, and a waveform shaping circuit 2 for shaping the reference signal output from the differential amplifier circuit 21 to generate a synchronization signal.
2, a 90 ° phase shift circuit 23 for shifting the phase of the reference signal output from the differential amplifier circuit 21 by 90 °, and
And a waveform shaping circuit 24 for shaping the reference signal output from the 0-degree phase shift circuit 23 to generate a synchronization signal. The reference signal output from the excitation circuit 14 is fetched and amplified, and then the waveform is obtained. The synchronization signal is shaped to generate a 0-degree synchronization signal, which is supplied to the resistance value detection circuit 17, and at the same time, a synchronization signal which is shifted by 90 degrees from the 0-degree synchronization signal is generated to generate the synchronization signal. Supply to 18.

Further, the differential amplifier circuit 15 is the excitation circuit 1 described above.
The ceramic humidity sensor 1 driven by 4
It is a circuit that takes in and amplifies the detection signal output from the device, and supplies the detection signal obtained by this amplification operation to the resistance value detection circuit 17 and the electrostatic capacitance detection circuit 18.

The resistance value detection circuit 17 is the differential amplifier circuit 1 described above.
5, the detection signal output from the synchronous signal generating circuit 16 is captured, and the detection signal is synchronously detected based on the 0-degree synchronization signal output from the synchronization signal generation circuit 16 to generate a resistance value signal indicating the resistance value of the ceramic element 5. Synchronous detection circuit 2 to generate
5, a differential amplifier circuit 26 that takes in and amplifies the resistance value signal output from the synchronous detection circuit 25, a variable resistor 27 that adjusts the impedance and amplification factor of the differential amplifier circuit 26, and the differential circuit The resistance value signal output from the amplifier circuit 26 is A / D converted to generate resistance value data A /
D conversion circuit 28, and the differential amplifier circuit 15
The detection signal output from the ceramic element 5 is acquired, and the detection signal is synchronously detected based on the 0-degree synchronization signal output from the synchronization signal generation circuit 16.
After the resistance value signal indicating the resistance value is generated, it is amplified and digitized to generate resistance value data indicating the resistance value of the ceramic element 5, and the resistance value data is supplied to the calibration unit 13.

The capacitance detection circuit 18 takes in the detection signal output from the differential amplifier circuit 15 and outputs the detection signal based on the 90-degree synchronization signal output from the synchronization signal generation circuit 16. A synchronous detection circuit 29 that performs synchronous detection to generate an electrostatic capacitance signal indicating the electrostatic capacitance of the ceramic element 5, and a differential amplifier circuit 30 that takes in and amplifies the electrostatic capacitance signal output from the synchronous detection circuit 29. A variable resistor 31 for adjusting the impedance and the amplification factor of the differential amplifier circuit 30, and the differential amplifier circuit 3
And an A / D conversion circuit 32 for A / D converting the electrostatic capacitance signal output from 0 to generate electrostatic capacitance data. The detection signal output from the differential amplifier circuit 15 is fetched and The detection signal is synchronously detected on the basis of the 90-degree synchronization signal output from the synchronization signal generation circuit 16 to generate a capacitance signal indicating the capacitance of the ceramic element 5, and then the capacitance signal is amplified. At the same time, it is digitized to generate capacitance data indicating the capacitance of the ceramic element 5, and the capacitance data is supplied to the calibration unit 13.

The temperature detecting section 11 is the temperature sensor 2
The reference contact compensation circuit 33 that takes in the thermoelectromotive force signal output from the device and compensates it with the voltage value at the reference temperature point to generate the temperature detection signal, and the temperature detection signal output from the reference contact compensation circuit 33. A differential amplifier circuit 34 that takes in and amplifies this, and an A / D conversion circuit 35 that A / D-converts the temperature detection signal output from the differential amplifier circuit 34 to generate temperature detection data are provided. , The temperature sensor 2
The thermo-electromotive force signal output from is taken in and compensated by the voltage value of the reference temperature point to generate the temperature detection signal, and after amplifying this, it is digitized to generate the temperature detection data. It is supplied to the calibration unit 13.

Further, as shown in FIG. 3, the storage unit 12 stores a magnetic disk device 36 in which various constant data necessary for calibrating the resistance value data and the capacitance data output from the humidity detecting unit 13 are stored. When a read command is supplied from the calibration unit 13, the contents corresponding to the read command are read out and supplied to the calibration unit 13.

In this case, as the contents stored in the magnetic disk device 36, for example, as shown in FIGS. 5 and 6, the electrical characteristics of the ceramic element 5 largely depend on the temperature, and the vertical axis indicates the resistance value R. Alternatively, when the logarithm of the capacitance C and the reciprocal of the absolute temperature T are plotted on the horizontal axis, a straight line is obtained as shown in FIG. 7 and FIG. R = Ar * exp {-Er / (G * T)} ... (1) C = Ac * exp {-Ec / (GT *)} ... (2) However, G: Gas constant T: Absolute temperature Ar: Experimentally obtained constants for each moisture content Er: Constants obtained for each moisture content Ac: Constants obtained for each moisture content Ec: Constants obtained for each moisture content

Therefore, in the magnetic disk device 36, the constants Ar, Er, Ac, E for each water content used in the Arrhenius equation shown in the above equations (1) and (2).
The value of c is stored, and the values of these constants Ar, Er, Ac, and Ec are read according to a read command from the calibration unit 13 and supplied to the calibration unit 13. Calibration unit 1
Reference numeral 3 includes a keyboard 37, a processing circuit 38, a printer device 39, a CRT device 40, and a magnetic disk device 41, and the resistance value output from the humidity detecting unit 10 based on the operation content of the keyboard 37. Data and capacitance data are taken in, and after calculating the water content W of the concrete 4 whose water content is to be measured based on these values of resistance data and capacitance data, the temperature detection unit Based on the value of the temperature detection data output from 11, the storage unit 12 is accessed to read the constants Ar, Er, Ac and Ec for each water content and based on the equations (1) and (2). The water content W is calibrated and printed out from the printer device 39, displayed by the CRT device 40, or stored in the magnetic disk device 41. .

The keyboard 37 has ten keys, function keys, various character keys, and the like. When these keys are operated to input various commands and various data, these various commands and various data are input. A key signal corresponding to the data is generated and supplied to the processing circuit 38.

The processing circuit 38 includes resistance value data and capacitance data output from the humidity detector 10, temperature detection data output from the temperature detector 11, key signals output from the keyboard 37, and the memory. Constants Ar, Er, Ac, Ec for each water content output from the part 12
CPU 43 configured by an input interface circuit 42 for fetching the data, a microprocessor, etc., for processing various commands, various data, etc. fetched by the input interface circuit 42, programs for controlling the operation of the CPU 43, and various programs. ROM 44 in which constant data is stored, a RAM 45 used as a work area of the CPU 43, and display data and print data output from the CPU 43, and the printer device 39 and The CRT device 40 and the output interface circuit 46 for outputting to the magnetic disk device 41 are provided.

Then, the resistance value data and the electrostatic capacitance data output from the humidity detecting section 10 are fetched based on the operation contents of the keyboard 37, and the water content is contained based on the respective values of the resistance value data and the electrostatic capacitance data. After calculating the water content W of the concrete 4 whose rate is to be measured, the storage unit 12 is accessed based on the value of the temperature detection data output from the temperature detection unit 10 for each water content. The constants Ar, Er, Ac and Ec are read out, the water content W is calibrated based on the equations (1) and (2), and this is calibrated to the printer device 39 or the CRT device 4.
0, supply to the magnetic disk device 41.

The printer device 39 is composed of a serial printer device, a laser printer device, etc., and when print data is output from the processing circuit 38,
After this is taken in and printed on the recording paper, the printed recording paper is ejected outside the device.

Further, the CRT device 40 is equipped with a menu screen for operating the entire water content measuring device and a CRT having a display capacity necessary for displaying the water content W, and the menu from the processing circuit 38. When the display data such as the screen or the water content W is output, the display data is fetched and displayed on the screen.

Further, the magnetic disk device 41 is a device used as a storage location of the measured data and the like of this moisture content measuring device, and when data such as the moisture content W to be stored is output from the processing circuit 38. , It is captured and stored in time series. Next, the water content measuring operation of this embodiment will be described with reference to the flowchart shown in FIG.

First, when the water content measuring device is powered on, a power supply circuit (not shown) operates to supply a power supply voltage to each part of the circuit to bring them into an operating state. The detection signal output from the ceramic humidity sensor 1 is captured by the temperature sensor 11 and the resistance value data indicating the resistance value of the ceramic element 5 and the capacitance data indicating the capacitance are output. The thermoelectromotive force signal output from the sensor 2 is captured and the temperature detection data is output. Further, in parallel with this operation, the CPU 43 of the processing circuit 38 operates to initialize each part of the processing circuit 38 (step ST1).

Thereafter, when a measurement start command is input from the keyboard 37, the CPU 43 of the processing circuit 38 starts the time counting operation and checks whether it is the sampling timing (step ST2), and at each sampling timing, The water content of the concrete 4 whose resistance value data and electrostatic capacity data output from the humidity detecting unit 10 are taken in and whose water content is to be measured based on each value of the resistance value data and the electrostatic capacity data After calculating the rate W (step ST3), the temperature detection data output from the temperature detection unit 11 is fetched (step ST4), and the storage unit 12 is accessed based on the value of the temperature detection data to obtain each moisture content. Each constant Ar, Er,
Ac and Ec are read out, the water content W is calibrated based on the equations (1) and (2), and this is printed out from the printer device, displayed by the CRT device 40, or the magnetic disk device. It is stored in 41 (step ST5).

Hereinafter, until a measurement end command is input from the keyboard 37 or the power is turned off (step ST
6) Every time the sampling timing comes, the CPU 43
Repeats the above-mentioned operation to obtain the water content W of the concrete 4.
Is measured, and is printed out from the printer device 39, displayed by the CRT device 40, or stored in the magnetic disk device 41 (steps ST2 to ST).
6).

As described above, in this embodiment, the resistance value data and the capacitance data output from the humidity detecting section 10 are fetched based on the operation contents of the keyboard 37, and the resistance value data and the capacitance data are also acquired. After calculating the water content W of the concrete 4 whose water content is to be measured on the basis of each value of, the storage unit 12 is accessed based on the value of the temperature detection data output from the temperature detection unit 11. Then, each constant Ar and E for each water content
Read r, Ac, and Ec to obtain the equations (1) and (2).
Since the water content W of the concrete 4 is calibrated based on the equation, the water content W of the concrete 4 can be instantly obtained without requiring human labor when the water content of the concrete 4 is obtained. The labor and time for measuring the water content can be reduced to almost zero, and the management of the concrete 4 can be automated.

Further, in the above-mentioned embodiment, the ceramic humidity sensor 1 and the humidity detecting section 10 of the measuring device body 3 are used.
The temperature sensor 2 and the temperature detection unit 11 of the measuring device body 3 are directly connected to each other. However, these can be separated from each other and a plurality of ceramic humidity sensors 1 are provided on the concrete 4 side. , A plurality of temperature sensors 2 are scattered and buried, and the humidity detection unit 1 of one measuring device main body 3 is embedded.
0 and the temperature detector 11 are detachably connected to any one of the ceramic humidity sensors 1 and the temperature sensor 2 corresponding to the ceramic humidity sensor 1, and the water content of the portion in which the ceramic humidity sensor 1 is embedded. You may make it measure W.

By doing so, the water content W of each part of the concrete 4 can be measured by one measuring device main body 3.

Further, a changeover switch is provided between the ceramic humidity sensor 1 and the humidity detecting section 10 of the measuring apparatus body 3 and between the temperature sensor 2 and the temperature detecting section 11 of the measuring apparatus body 3. Any one of the ceramic humidity sensors 1 and the temperature sensor 2 corresponding to the ceramic humidity sensor 1 are selected and used as the humidity detecting unit 10 of the measuring device body 3 and the temperature detecting unit 11 of the measuring device body 3. You may make it respectively connect.

Further, in the above-mentioned embodiment, the ceramic element 5 constituting the ceramic humidity sensor 1 based on the detection signal output from the ceramic humidity sensor 1.
Is calculated and the water content W of the concrete 4 is calculated based on the resistance value and the capacitance. However, based on the detection signal output from the ceramic humidity sensor 1. The ceramic humidity sensor 1
Either the resistance value or the electrostatic capacitance of the ceramic element 5 constituting the
May be calculated.

Further, in the above-described embodiment, each constant A for each moisture content is stored in the magnetic disk device 36 of the storage unit 12.
r, Er, Ac, Ec are stored, and the water content W is calculated by performing the operations shown in the equations (1) and (2) based on the constants Ar, Er, Ac, Ec for each water content. Although it is calibrated, each constant A for each water content
The r, Er, Ac, and Ec may be stored in the ROM 44 of the processing circuit 38 or the magnetic disk device 41 of the calibration unit 13.

When the storage capacity has a margin, a calibration table is prepared from the tables shown in FIGS. 7 and 8 in place of the constants Ar, Er, Ac and Ec for each water content. The calibration table is stored in the magnetic disk device 36 of the storage unit 12, the ROM 44 of the processing circuit 38, the calibration unit 13
When the water content W is stored in the magnetic disk device 41 and the water content W is calibrated, the water content W is calculated based on the calibration table.
May be calibrated.

[0042]

As described above, according to the present invention, when determining the water content of concrete, it is possible to instantly determine the water content of concrete without requiring manpower.
As a result, the labor and time for measuring the water content of concrete can be reduced to almost zero, and concrete management can be automated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a water content measuring apparatus according to the present invention.

FIG. 2 is a block diagram showing a detailed circuit configuration example of a ceramic humidity sensor, a humidity detecting unit, a temperature sensor, and a temperature detecting unit shown in FIG.

3 is a block diagram illustrating a detailed circuit configuration example of a calibration unit and a storage unit illustrated in FIG.

FIG. 4 is a flowchart showing an example of a water content measurement operation of the water content measurement apparatus shown in FIG.

5 is a graph showing an example of resistance value / temperature characteristics of the ceramic humidity sensor shown in FIG.

FIG. 6 is a capacitance of the ceramic humidity sensor shown in FIG.
It is a graph which shows an example of a temperature characteristic.

7 is a graph showing an example of a graph when the resistance value / temperature characteristic of the ceramic humidity sensor shown in FIG. 1 is logarithmically converted.

FIG. 8: Capacitance of ceramic humidity sensor shown in FIG.
It is a graph which shows the example of a graph at the time of carrying out the logarithmic conversion of the temperature characteristic.

[Explanation of symbols]

 1 Ceramic Humidity Sensor 2 Temperature Sensor 3 Measuring Device Main Body 4 Concrete 10 Humidity Detection Section 11 Temperature Detection Section 12 Storage Section (Temperature Characteristic Data Storage Section) 13 Calibration Section (Water Content Calculation Section)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroki Kazumi, Inventor Hiroki Kazumi, 2-1-1, Tobita, Chofu-shi, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor, Hiroshi Kasai 2--19-1, Tobita, Chofu, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor Junji Okamura 1-2-7 Moto-Akasaka Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Inventor Shuji Emori 1-8-1, Minamimagome, Ota-ku, Tokyo Stock Incorporated Ketto Scientific Research Institute (72) Inventor Hiroshi Masuma 1-8-1 Minamimagome, Ota-ku, Tokyo Incorporated Ketto Scientific Research Institute

Claims (2)

[Claims] 1. A ceramic humidity sensor embedded in concrete whose water content is to be measured, a temperature sensor embedded in a portion of the concrete corresponding to the ceramic humidity sensor, and the ceramic humidity. A humidity detecting unit that calculates the humidity of the concrete based on a detection signal output from a sensor, a temperature detecting unit that calculates the temperature of the ceramic humidity sensor unit based on a detection signal output from the temperature sensor, and A temperature characteristic data storage unit that stores temperature characteristic data of a ceramic humidity sensor, the humidity of the concrete obtained by the humidity detecting unit, the temperature of the ceramic humidity sensor unit obtained by the temperature detecting unit, and the temperature. The water content of the concrete based on the temperature characteristic data stored in the characteristic data storage unit Moisture content measuring device, characterized in that it and a moisture content calculator for calculating. 2. The moisture content measurement according to claim 1, wherein the temperature characteristic data of the ceramic humidity sensor stored in the storage unit is each constant when the temperature characteristic of the ceramic humidity sensor is approximated by an Arrhenius equation. apparatus.